Optical magnification device for distance variation

ABSTRACT

An optical magnification device for varying the distance between an observer&#39;s eye ( 1 ) and an object ( 7 ), e.g., for a binocular magnifier or a microscope, in which focusing onto the object ( 7 ) is accomplished by means of progressive and/or multifocal lenses ( 3 ) displaceable perpendicular to the observation beam(s) ( 2 ).

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of the German patent application102 01 835.9, filed Jan. 18, 2002, which is incorporated by referenceherein.

FIELD OF THE INVENTION

[0002] The invention concerns an optical magnification device, forexample a binocular magnifier or a microscope, which permits a variationin the distance between an observer's eye and an object.

BACKGROUND OF THE INVENTION

[0003] A property often demanded for microscopes and binocularmagnifiers is that the working distance of the optical device be capableof modification within a specific range, typically between 200 mm and400 mm (also called the “focusing range”). At present, this is achievedby the fact that at least one optical element (for example, a lenselement or a lens group) is shifted axially in the optical axis,bringing about a modification in focal length. This usually results in achange in overall length, cf. “Sigma Lens Catalog,” Tokyo 201, 3 pages(no publication data), obtained in year 2000.

[0004] A presbyopic eye (having a lens no longer capable ofaccommodation) sees clearly only at one specific distance. Thisdisadvantage is overcome by the use of eyeglasses. Lens elements in theform of a progressive lens have also recently become available. In aprogressive lens, the refractive power of the corrective lens changeslaterally (non-axially) over the surface of the eyeglass lens. As theeye looks through the areas of differing refractive power, for examplefrom top to bottom, it can then see clearly at different distancesdespite poor accommodation.

[0005] Progressive lenses used today are made of inorganic optical glassmaterials or of plastics, e.g. polycarbonate, etc.

[0006] In the past, instead of progressive lenses, multifocal lensesthat possess different zones with differing refractive powers were oftenused because they are easier to manufacture. These also allow the userto see clearly at different distances without accommodation by the lensof his or her own eye.

[0007] It is recognized that focusing on an object by means of axiallydisplaceable lens elements or lens groups, as in the case ofconventional microscopes, binocular magnifiers, etc., is disadvantageousin terms of the following aspects:

[0008] a) Changes in overall length.

[0009] b) Greater weight because of greater overall length.

[0010] c) Complex design solutions in some cases, if focusing is tooccur in “open space,” i.e., without a fixed housing having thecorresponding mechanisms, for example in a binocular magnifier.

[0011] d) Lens groups are difficult to exchange, and the range ofapplication for binocular magnifiers or microscopes is thereforelimited.

SUMMARY OF THE INVENTION

[0012] It is therefore the object of the present invention to create adevice which permits focusing on an object without axial shifting oflens elements and/or lens groups.

[0013] This object is achieved by the use of a progressive or multifocallens, known per se, in or on the binocular magnifier or in or on themicroscope.

[0014] This technical innovation is based on the principle ofconventional multifocal lenses or progressive eyeglasses, cf. thebrochure entitled “Zeiss Brillengläser 1985 [Zeiss eyeglasses 1985],”Document no. 20-955-d, I/85, January 1985.

[0015] If a progressive lens (described therein) is moved in front of orbehind an optical instrument, focal length modification is thusobtained. In order to bring about the focal length modification, themovement of the lens is accomplished approximately perpendicular to theoptical axis—in contrast to the known methods with axial shifting of thelens elements. For practical reasons, the progressive lens should beused in the closest possible proximity to the pupil. This also makespossible easy exchangeability of the progressive or multifocal lens,thus creating different ranges of application.

[0016] Further possible applications are, for example, eyepieces,binoculars, telescopes, photographic lenses, and many other opticalinstruments that require focusing, focal length modification, or workingdistance modification.

[0017] The invention utilizes progressive or multifocal lenses known perse, but for a different purpose, i.e., not for the correction ofdefective vision but for modification of the focal length of an opticalmagnification device.

[0018] The following improvements are obtained by way of the devicedescribed herein:

[0019] Short overall lengths;

[0020] Low weight.

[0021] Usability in all optical instruments that require focusing, focallength modification, or working distance modification.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The invention will be explained in more detail, by way ofexample, with reference to the figures in which:

[0023]FIG. 1 shows a first embodiment of an optical device according tothe present invention for distance variation (binocular magnifier);

[0024]FIG. 2 shows a second embodiment according to the presentinvention (microscope).

DETAILED DESCRIPTION OF THE INVENTION

[0025] In FIG. 1, light emitted or reflected by object 7 is directed viaa binocular magnifier 5, joined by immovable connection 6, to twoprogressive lenses 3, guided together by common guidance system 4, whichare arranged in the optical axis 2 of each of the observer's eyes 1.Light incident on progressive lenses 3 is refracted thereat anddeflected to observer's eyes 1.

[0026] In order to achieve a focal length modification or a variation inthe distance between observer's eye 1 and object 7, progressive lenses 3are arranged displaceably in the lateral (non-axial) direction. In thecontext of stereoscopic viewing, the two progressive lenses 3 aredisplaced in parallel fashion. For that purpose, they are immovablyconnected to one another by common guidance system 4, in the context ofbinocular magnifier 5 shown here.

[0027] The entire system is embodied, for example in the applicationdepicted here for a binocular magnifier, as an eyeglass frame;adjustment of the progressive lenses can be performed manually, by wayof a drive system, or also in motorized fashion.

[0028] Instead of the up-and-down movement of progressive lenses 3,displacement can also occur on a circular arc segment in accordance withspherical double arrow 11, shown in FIG. 1; all that must be achieved,according to the present invention, is that zones of differingrefractive power are successively pivoted in front of the pupil of theoptical instrument (for example, in front of binocular magnifier 5). Theinvention of course also encompasses lateral (non-axial) displacementmovements of progressive lenses 3.

[0029]FIG. 2 schematically depicts an optical device according to thepresent invention for distance variation, with reference to the exampleof a microscope.

[0030] Light striking the shared main objective 8 is refracted thereatand deflected to respective progressive lenses 3 (cf. double arrows 12),which are displaceable in a direction perpendicular to optical axes 2 ofthe two observation beams and are each located between main objective 8and zoom 9. The light beams refracted at progressive lenses 3 areconveyed via zoom 9 to eyepiece tube 10.

[0031] A displacement of progressive lens 3 perpendicular to opticalaxis 2 of the observation region results in differing focal values (fromobserver's eye 1 to object 7).

[0032] The invention is not limited to stereoscopic beam paths, butrather is suitable also for monocular optical systems.

[0033] As a variant of the invention, as already mentioned, it is alsopossible to use a multifocal lens (which results in discontinuous focalranges) instead of the progressive lens, or to use a combination of thetwo.

[0034] While the invention has been described in connection with certainembodiments, the description is not intended to limit the scope of theinvention to the particular forms set forth, but, on the contrary, it isintended to cover such alternatives, modifications, and equivalents asmay be included within the spirit and scope of the invention as definedby the appended claims.

PARTS LIST

[0035]1 observer's eye(s)

[0036]2 optical axis/axes of the two observation beams

[0037]3 progressive lens or multifocal lens(es)

[0038]4 common guidance system

[0039]5 binocular magnifier

[0040]6 immovable connection

[0041]7 object

[0042]8 main objective

[0043]9 zoom

[0044]10 eyepiece tube

[0045]11 spherical double arrow (displacement on a circular arc segment)

[0046]12 double arrow (displacement)

[0047]13 motorized drive system

[0048]14 autofocus system

[0049]15 control unit

What is claimed is:
 1. An optical magnification device comprising: anoptical axis; at least two lens elements on said optical axis forfocusing an observation beam; wherein said at least two lens elementsincludes a progressive lens that is non-axially displaceable relative tosaid optical axis for changing a focal length of said opticalmagnification device.
 2. The optical magnification device of claim 1,wherein said progressive lens is displaceable along an arcuate path. 3.The optical magnification device of claim 1, wherein said progressivelens is selectively removable from said optical axis.
 4. The opticalmagnification device of claim 1, wherein said progressive lens isexchangeable with another progressive lens having different opticalcharacteristics.
 5. The optical magnification device of claim 1, whereinthe non-axial displacement of said progressive lens is manuallycontrollable.
 6. The optical magnification device of claim 1, furthercomprising a motorized drive system connected to said progressive lensfor controlling the non-axial displacement of said progressive lens. 7.The optical magnification device of claim 6, wherein said motorizeddrive system includes an automatic focusing system and an electronicevaluation and control unit.
 8. The optical magnification device ofclaim 1, wherein said optical magnification device comprises a mainobjective lens and a zoom system, and said progressive lens is locatedbetween said main objective lens and said zoom system.
 9. A stereoscopicoptical magnification device comprising: a pair of optical axes, each ofsaid pair of optical axes having at least two lens elements thereon forfocusing a respective observation beam, wherein said at least two lenselements includes a respective progressive lens that is non-axiallydisplaceable with respect to said optical axis for changing a focallength of said optical magnification device along said optical axis;wherein said progressive lens on one of said pair of optical axes iscoupled with said progressive lens on another of said pair of opticalaxes such that said coupled progressive lenses are non-axiallydisplaceable relative to said pair of optical axes in unison.
 10. Anoptical magnification device comprising: an optical axis; at least twolens elements on said optical axis for focusing an observation beam;wherein said at least two lens elements includes a multifocal lens thatis non-axially displaceable relative to said optical axis for changing afocal length of said optical magnification device.
 11. The opticalmagnification device of claim 1, wherein said multifocal lens isdisplaceable along an arcuate path.
 12. The optical magnification deviceof claim 1, wherein said multifocal lens is selectively removable fromsaid optical axis.
 13. The optical magnification device of claim 1,wherein said multifocal lens is exchangeable with another multifocallens having different optical characteristics.
 14. The opticalmagnification device of claim 1, wherein the non-axial displacement ofsaid multifocal lens is manually controllable.
 15. The opticalmagnification device of claim 1, further comprising a motorized drivesystem connected to said multifocal lens for controlling the non-axialdisplacement of said multifocal lens.
 16. The optical magnificationdevice of claim 6, wherein said motorized drive system includes anautomatic focusing system and an electronic evaluation and control unit.17. The optical magnification device of claim 1, wherein said opticalmagnification device comprises a main objective lens and a zoom system,and said multifocal lens is located between said main objective lens andsaid zoom system.
 18. A stereoscopic optical magnification devicecomprising: a pair of optical axes, each of said pair of optical axeshaving at least two lens elements thereon for focusing a respectiveobservation beam, wherein said at least two lens elements includes arespective multifocal lens that is non-axially displaceable with respectto said optical axis for changing a focal length of said opticalmagnification device along said optical axis; wherein said multifocallens on one of said pair of optical axes is coupled with said multifocallens on another of said pair of optical axes such that said coupledmultifocal lenses are non-axially displaceable relative to said pair ofoptical axes in unison.